#import "ViewController.h"@interface ViewController ()<UIPickerViewDataSource,UIPickerViewDelegate>{    NSArray *pickerArray;}@property (weak, nonatomic) IBOutlet UIPickerView *myPickerView;@end@implementation ViewController- (void)viewDidLoad{    [super viewDidLoad];    _myPickerView.dataSource=self;    _myPickerView.delegate=self;    _myPickerView.showsSelectionIndicator=YES;    pickerArray=[NSArray arrayWithObjects:@"1",@"2",@"3",@"4",@"5",@"6",@"7",@"8",@"9",@"10", nil];   }- (void)didReceiveMemoryWarning{    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}-(NSInteger)numberOfComponentsInPickerView:(UIPickerView *)pickerView{    return 3;}-(NSInteger)pickerView:(UIPickerView *)pickerView numberOfRowsInComponent:(NSInteger)component{    return pickerArray.count;}-(UIView *)pickerView:(UIPickerView *)pickerView viewForRow:(NSInteger)row forComponent:(NSInteger)component reusingView:(UIView *)view{    CGRect rect=CGRectMake(0, 0, [self pickerView:pickerView widthForComponent:row], [self pickerView:pickerView rowHeightForComponent:row]);    UIView *testView=[[UIView alloc]initWithFrame:rect];    [testView setBackgroundColor:[UIColor clearColor]];    [testView setOpaque:YES];    UILabel *label=[[UILabel alloc]initWithFrame:CGRectMake(8, 0, [self pickerView:pickerView widthForComponent:row]-16.0f, [self pickerView:pickerView rowHeightForComponent:row])];    [label setBackgroundColor:[UIColor clearColor]];    label.textAlignment=NSTextAlignmentCenter;    label.text=pickerArray[row];    switch (row)    {        case 1:        case 2:        {            testView.backgroundColor=component==0?[UIColor greenColor]:[UIColor blueColor];        }        case 3:        {            testView.backgroundColor=component==0?[UIColor brownColor]:[UIColor redColor];        }        break;        default:        {            testView.backgroundColor=component==0?[UIColor grayColor]:[UIColor orangeColor];        }        break;    }    label.font=[UIFont boldSystemFontOfSize:14.0f];    [testView addSubview:label];    return testView;}//可有可无-(NSString *)pickerView:(UIPickerView *)pickerView titleForRow:(NSInteger)row forComponent:(NSInteger)component{    return pickerArray[row];}- (CGFloat)pickerView:(UIPickerView *)pickerView widthForComponent:(NSInteger)component;{    return 120;}-(CGFloat)pickerView:(UIPickerView *)pickerView rowHeightForComponent:(NSInteger)component{    return 50;}- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component{         NSLog(@"row=%ld",row);}